New high-school transfer student Na-Mi
(Shim Eun-Kyung) comes from a small town in Jeolla Province to her new school
in the capital city of Seoul. When she is nervous, her small town dialect comes
out & she starts to shake.On her first day at her new school she is bullied
by others. Coming to her help is a group of girls. The girls are Chun-Hwa (Kang
So-Ra) - known for her strong sense of loyalty & excellant fighting skills,
heavyset Jang-Mi (Kim Min-Young) - who badly wishes to have plastic surgery to
get double eye-lids, Jin-Hee (Park Jin-Joo) - excellent when it comes to
spewing profanity, Geum-Ok (Nam Bo-Ra) - interested in literature, Bok-Hee (Kim
Bo-Mi) - dreams of one day becoming Ms. Korea and Su-Ji (Min Hyo-Rin) - always
arrogant. Na-Mi quickly becomes part of their group. When the group confronts
rival girls known as Sonyeo Sidae ("Girls Generation"), Na-Mi spews
curse words she picked up from her grandmother. Because of Na-Mi the girls are
able to avoid a crisis. These seven girls then form their own group named
"Sunny". They also vow to stay together forever. The girls then
prepare for a performance at an upcoming school festival, but on the day of
their performance a terrible event occurs leading the girls to eventually going
their own separate ways.

Twenty five years later, Na-Mi (Yoo
Ho-Jeong) is married to a successful businessman and has a beautiful daughter.
Her life seems perfect from afar, but there's something lacking in her life.
One day, Na-Mi bumps into high school friend Chun-Hwa (Jin Hee-Kyung) in the
hospital. They are ecstatic to see each other, but Na-Mi receives a phone call
and has to leave. On her way out she ask Chun-Hwa if there is anything she can
do for her. Chun-Hwa at first says no, but after a moment of reflection she
makes a simple request to Na-Mi. Chun-Hwa asks Na-Mi to find the other members
of "Sunny," so she can see them one more time ...